spudgun range, are we falling short?

[MrCrowley]

Wow that's looking great!

An aluminium backplate shouldn't add too much weight I don't think. The thinnest aluminium you've got would do the job.

[al-xg]

Even something like a cardboard disk would probably insulate it enough to prevent melting.

Plug diameter is 48mm, just a tad smaller than the bore, because the friction should came from the petals edge only.

How is the projectile sealed in the bore ?

[LeMaudit]

Wow that's looking great!
An aluminium backplate shouldn't add too much weight I don't think. The thinnest aluminium you've got would do the job.

Yes, I will drill some holes in the UHMW, so the weight of the aluminum will not add much really. And a hole in the center will bolt the aluminum disk to the plug and will be used to support the petals just a bit with a custom thingy. I have to do something with those nice chicago bolts... You'll see

I'm thinking that you could give a try to this sabot with a mockup MiniBoy first. Just too see if it open all right and the projectile fly strait. After all, the design is simple enough to be replicate without much effort and tooling by others for different projectile shape, so I think it worth some experiments. Of course I'll try to over-engineer it, but that's just me

Even something like a cardboard disk would probably insulate it enough to prevent melting.

Probably. But not as fun to do

[al-xg]

Even something like a cardboard disk would probably insulate it enough to prevent melting.

Probably. But not as fun to do

In that case I would sat make your own honeycomb composite wad

[LeMaudit]

In that case I would sat make your own honeycomb composite wad

You know what? You might have something there

Nah, seriously I'll just make a thin disk with a little recess that fit the UMMW, it will protect the edge from melting and also will add some rigidity.

I know, I know...

[MrCrowley]

As for the mock-up testing, should I fire them from one of my pneumatic cannons? Less risk damaging the sabot and it will limit the range of the mock-up projectile.

[LeMaudit]

Well, if the sabot is damaged, I guess it will mean that it didn't fire strait. The way it is made following JSR idea (again! ) should not put stress on the parts if they exit nicely from the barrel. And I can always make another one plenty of UHMW left.
I was thinking of a mockup ammo just not to loose the real shiny MiniBoy during testing

Are your other cannons made with the same bore 48.5mm? It could be a good idea to fire slow after all, to be able to see on slow-mo if the separation is done well.

[MrCrowley]

Are your other cannons made with the same bore 48.5mm? It could be a good idea to fire slow after all, to be able to see on slow-mo if the separation is done well

No, but I should be able to swap the barrels on the launchers if I buy a 40mm x 50mm female x male threaded bushing. My 1.5" porting piston valve pneumatic has 2" barrel threads and so does my 2" sprinkler valve pneumatic.

I will also be able do slow-mo footage. If velocity was around 50m/s over a distance of 3m and I filmed at 420fps, I should get 30 frames of the projectile and sabot. Though I doubt 3m would be enough to catch the sabot falling away from the projectile. Perhaps 5m would do it?

[jackssmirkingrevenge]

Looking good! I'm confident you can shave off a lot of weight with some attention to the petals, drilling holes and bevelling and such - and as mentioned above the thinnest of ali plates should be enough as a backplate - polished of course

[dewey-1]

What are the dimensions of the rectangles and plug thickness?

Why not use adhesive backed aluminum tape. It could be replaced easily enough or even double layered if required.

[jackssmirkingrevenge]

I will also be able do slow-mo footage. If velocity was around 50m/s over a distance of 3m and I filmed at 420fps, I should get 30 frames of the projectile and sabot. Though I doubt 3m would be enough to catch the sabot falling away from the projectile. Perhaps 5m would do it?

You could also try filming down the barrel.

Why not use adhesive backed aluminum tape. It could be replaced easily enough or even double layered if required.

Sounds like a good idea, I'm confident that the design is supported enough to survive a reasonable mix without the need for a significant metal plate backing.

[MrCrowley]

You could also try filming down the barrel

Ah, good idea


Just over a month on since the start of this topic (seemed longer), are you so far satisfied with the response and outcome, Jack?

[jackssmirkingrevenge]

Just over a month on since the start of this topic (seemed longer), are you so far satisfied with the response and outcome, Jack?

To be honest I expected a few interested replies but for the topic to fade within a week, so I'm amazed at the response.

Credit goes to everyone for brainstorming but in particular LeMaudit's fine machining is to be commended - though in some ways it has been counter productive, who on earth would want to fire such a work of art? Ah yes, you - and credit also to Duane for the detailed drawings of the whole proceedings.

I've also been privy to some similar projectile optimisation development work outside of the forum which has yielded fantastic results from what I've seen I really would like to see more of these sort of projects, they bring out the best of the forum and really it's what spudfiles should be about

[MrCrowley]

I really would like to see more of these sort of projects, they bring out the best of the forum and really it's what spudfiles should be about

Well, you've got my vote for Mayor

[jackssmirkingrevenge]

Sorry for making it sound like a cheesy political party manifesto

Still, at least it wasn't passive agressive